Our goal is to investigate whether an elementary school program for at- risk children has impact on early adolescent drug use. Our proposed research addresses this issue by linking together an existing drug prevention program for at-risk children (the ALPHA program) with an existing annual survey (the Omnibus Survey). The ALPHA Program is a school-based drug prevention program targeting 4th and 5th graders with aggressive behavior, social withdrawal, learning problems, and low self- competence. The program is operated by Operation PAR, in cooperation with the Pinellas County School Board. The semester-long "pull-out" program intervenes with the targeted risk behaviors through behavior management strategies, social skills strategies, and curricular and instructional strategies. We are examining the impact of the ALPHA Program on age of initiation of use, frequency of use, and problem use through a field experiment with internal and external controls. Our sample is drawn from the Omnibus Cohort, a cohort of children followed prospectively with annual parent and teacher surveys throughout their school career (199O-2OO2). The Omnibus cohort will become eligible for the ALPHA Program in Fall 1993, and we have negotiated to augment the Omnibus Survey from 1993-1997 (3rd grade - 7th grade) with measures of impact and relevant covariates for our research. We are also proposing to extend our examination of impact by investigating the costs and benefits of the ALPHA Program. As public expenditures on drug prevention and treatment have increased, policy- makers are seeking information to assess the costs and benefits of alternate policies and programs. This project provides a unique opportunity to rigorously evaluate the outcomes of a drug prevention program, to document the cost of achieving the outcomes, and to assess whether the benefits of the program exceed the cost. We will develop and implement a protocol to assess the costs and benefits of the drug prevention program, and produce a technical assistance manual for drug prevention costs and benefits research.